Pressure-sensitive adhesive optical film and method for producing same

Abstract

Disclosed is to provide a pressure-sensitive adhesive optical film that has excellent durability wherein deterioration of an image display region is suppressed even under severe conditions such as heating caused by lighting of a backlight and to provide a method for producing the same. Disclosed is also to provide an image display using such a pressure-sensitive adhesive optical film. A pressure-sensitive adhesive optical film, comprising: an optical film; and a pressure-sensitive adhesive layer arranged on one or both sides of the optical film, wherein the pressure-sensitive adhesive layer is made from a pressure-sensitive adhesive composition comprising 100 parts by weight of a (meth)acrylic polymer which contains, as a monomer unit, at least 50% by weight of an alkyl (meth)acrylate ester having an alkyl group with 4 or more carbon atoms, and 0.02 to 2 parts by weight of a peroxide, and the pressure-sensitive adhesive layer has a thickness of 20 μm or more.

1 . A pressure-sensitive adhesive optical film, comprising: an optical film;
 and a pressure-sensitive adhesive layer arranged on one or both sides of the optical film, wherein the pressure-sensitive adhesive layer is made from a pressure-sensitive adhesive composition comprising 100 parts by weight of a (meth)acrylic polymer which contains, as a monomer unit, at least 50% by weight of an alkyl (meth)acrylate ester having an alkyl group with 4 or more carbon atoms, and 0.02 to 2 parts by weight of a peroxide, and the pressure-sensitive adhesive layer has a thickness of 20 μm or more.   
     
     
         2 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the pressure-sensitive adhesive composition further comprises 0.01 to 2 parts by weight of an isocyanate crosslinking agent based on 100 parts by weight of the (meth)acrylic polymer. 
     
     
         3 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the pressure-sensitive adhesive composition further comprises 0.01 to 1 part by weight of a silane coupling agent based on 100 parts by weight of the (meth)acrylic polymer. 
     
     
         4 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the (meth)acrylic polymer further comprises, as a monomer unit, 0.01 to 5% by weight of an hydroxyl group-containing monomer. 
     
     
         5 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the (meth)acrylic polymer is free of a functional group reactive with an isocyanate group. 
     
     
         6 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the (meth)acrylic polymer has a weight average molecular weight of 1,000,000 or more. 
     
     
         7 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the pressure-sensitive adhesive layer has a gel fraction of 40 to 95% by weight. 
     
     
         8 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the pressure-sensitive adhesive layer has a thickness of 25 to 40 μm. 
     
     
         9 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the optical film is a laminate comprising a compensation film. 
     
     
         10 . The pressure-sensitive adhesive optical film according to  claim 9 , wherein the compensation film comprises an obliquely oriented discotic liquid crystal layer. 
     
     
         11 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the optical film is a laminate comprising a polarizing plate. 
     
     
         12 . The pressure-sensitive adhesive optical film according to  claim 1 , wherein the optical film is at least 8 inches in size. 
     
     
         13 . A method for producing a pressure-sensitive adhesive optical film, including the steps of forming a layer comprising a pressure-sensitive adhesive composition on one or both sides of an optical film, and crosslinking the pressure-sensitive adhesive layer with a peroxide, wherein the pressure-sensitive adhesive layer is made of the pressure-sensitive adhesive composition containing 100 parts by weight of a (meth)acrylic polymer which contains, as a monomer unit, at least 50% by weight of an alkyl (meth)acrylate ester having an alkyl group with 4 or more carbon atoms, and 0.02 to 2 parts by weight of a peroxide, and the pressure-sensitive adhesive layer has a thickness of 20 μm or more. 
     
     
         14 . The method according to  claim 13 , wherein the pressure-sensitive adhesive composition further comprises 0.01 to 2 parts by weight of an isocyanate crosslinking agent based on 100 parts by weight of the (meth)acrylic polymer. 
     
     
         15 . The method according to  claim 13 , wherein at least 50% by weight of the peroxide is decomposed by the crosslinking step. 
     
     
         16 . The method according to  claim 13 , wherein the pressure-sensitive adhesive layer has a gel fraction of 40 to 95% by weight. 
     
     
         17 . The method according to  claim 13 , wherein the optical film is a laminate comprising a compensation film. 
     
     
         18 . The method according to  claim 17 , wherein the compensation film comprises an obliquely oriented discotic liquid crystal layer. 
     
     
         19 . An image display, comprising a laminate comprising the pressure-sensitive adhesive optical film according to  claim 1 .